Means for increasing the illuminating power for corrugated lenses



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MEANS FOR INCIIHASINCIA THE ILLUMINATING POWER FOR CORRUGATED LENSES Filed Feb. 2'5. 1922 In non [50':` Henr'g Phelps Patented July 8, 1924.

UNiTeDjfsTATEs PATENT ermee.

HENRY PHELPS GAGE, F CORNING. NEW YORK. .ASSIGNOR TO COR-NING GLASS VTORKS,1

0F COBNING, NEW YORK. A CORPORATION 0F NEW lYORK.

MEANS FOR INCREASING THE ILLUMINATING vPOWER FOR CORRGATED LENSES.

Original application tiled-October 29, 1920, Serial No. 420,412. Divided a Serial No.4 539,099.

T 0 allie/10m, 1i-may concern Be it known that I, HENRY PHELPS GAGE, a citizen of the United States oAmerica, and a resident of Corning, in the count-y of 6 Steuben, State of New York, have invented certain new and useful Improvements in Means for Increasing the Illuminating Power for Corrugated Lenses, of which the following is a specification. This application is a division of my a cation Serial Number' 420,412, filed October 29, 1920, for means for increasing the illuminating power for corrugated lenses.

As is "well known, the light flux delivered by a lens is greater, the greater the angle it subtends at the -light source.- It has, of

course, been 'further proposed to increase,

the. illuminating ower by the use of a reflector situated be ind the light source. To increase the angle of light utilized beyond a certain amount, introduces difficulties, in the design of lenses, owing to the extreme angles through which the light must be retracted, and also to reflection losses and to other Similar causes, as is well known in the art., My invention, therefore, has for its pur# ose to increase the illuminatingr power of enses by utilizing a mirror. and so directing the rays reflected thereby, that the refractive faces in the lenses utilized for the proper direction of such rays,v are faces which are utilized in the refraction of the light from a direct source, and hence may be shaped as desired, and this I preferably accomplish by utilizing an inverted corrugated or Fresnel lens in which the. steps of the zones are utilized for the refraction of the direct rays from the light source and the risers, for the refraction of the rays refieeted from the mirror. v

For its more ent invention has as its object the provision of a system in which combined parallel and converging beams of light are projected.

A further object of my present invention is to provide a system in which the divergent rays from the light source are projected through the risers of the lens and produce a fconverging beam, while the 'direct rays from the light source are projected lpiligh the steps of the lens in a parallel The fmirror utilized is an annular one, and

' of the drawing,

particular purpose, my pres' d this application filed February of the transverse plane of the light source, being of greater diameter than that part of the lens which it is intended to use in the transmission ot the retracted light, as will be scribed and claimed.

Referring to the accompanying drawings,-

The ligure is a longitudinal sectional cen? tral view through a Fresnel lens arid mirror system embodying the invent-ion.

Referring more particularly to Figure 1 the lens A, is shown as an inverted corrugated lens, the steps ct?, a2 etc., of -which are so formed as to have the same focus, and to project light rays falling directly on the rear face of the lens from the light source' B,-located at the principal focal pointI B of the system, in a parallel beam, as is shown by t-he full lines B-a1, d1, B-az, defel, as is Well known.

n annularmirror C1, in the form of a is placed in front smooth or corrugated "conoidal frustrum, is

symmetrically- -located around the principal axis `E of the system, between the light source, and the rear of the lens. T he wall of the mirror C1 is inclined to such an angle with the axis' B-E of the system, thaigmys B-e. B--CT-etc.. from the lightsource B, are too divergent to strike the rea-r face of the lens Anand falling onk the mirror, are' reflected, wholly orsubstantially so to the rear of the lens, a` d after vpassing therethrough, impinge on the annular risers a, a, etc., at such angles that they are projected in a converging beam. Thusfinthis form ofthe in.

`vention, from ,the light sou the lens, form a focus different fromthatof the lens, should the latter be used without the mirror C, while the directfrays from the light source are proiected through the lens in a parallel beam. Thus the. light rays which pass through the lens, provide a system having a focus diiierent from that of the lens, should the latter be used Without the mirror C;

As far as ossible, it is desirable to so arrange and slape the parts making up the system that the risers and steps are each e BLwhich pass through parallel, or substantially parallel to therays (direct or reflected)\passing through .;.-'the las @einem thermen@ impinaregaahe" the reieted divergent light raysv hereinafter more fully deconverging-beam having a ics Q y v1,500,185

steps or risers, respectively, adjacent thereto, to prevent diffusion of light rays duo to the same falling on faces not. 'shaped to properly direc-t the same.

It is also to be understood that a mirror can also be used back of the light source if desired, and that the use of such mirror in no mannerhinders or prevents satisfactory reflection of the aninilar retlecting mirror herein described. Having thus described my invention what .I desire to secure by Letters Patent is,- 1. In an optical s` stem, the combination of a corrugated lens aving steps and risers, a light Source, and 1 c'onoidel' mirror posi tioned between the lens and light source, the parts being so arranged that rays falling'on the lens directly from4 thelight-souree pass through the lens substantially parallel with the faces ofthe adjacent risers und arerefraoted by the. steps in a substantially' parallel bundle, and vthat rays falling on'the lens after reflection by the mirror pass through the lens substantially parallel with the adjacent :steps und ure projected by the risers in a converging benin.

2. Anoptlcnl s vsteni ineludlng 1n combination, zx corrugated eondensing'lens hnvmg steps und risers, u light source. and 2i mirror positioned between the lons und light, source tor the purpose of reflecting rays from the light source through therisers ofv Suid lens, Suid system having n focus differvnl l'ronl (hat of the lens alone.' i

3. ln un optical system, the combination ola corrugated -condensing lens haring steps and risers. n light source, and :i conoidul mirror positioned between said lens :ind- 

